Monoazo dyestuffs



Patented Feb. 27, 1951 MSNOAZO DYESTUFFS Willy Steinemann, Basel, Switzerland, assignor to Sandoz Limited, Basel, Switzerland No Drawing. Application April 26, 1948, Serial No. 23,402. in Switzerland April 29, 1947 5 Claims.

1 The present invention relates to new chromable monoazo dyestuffs. It has been found that new monoazo dyestuffs maybe obtained by coupling in an alkaline medium a diazotized o-aminophenol sulfonic acid, which can be substituted in the nucleus by halogen, sulfo, nitro, NH-acyl or NH.COO lower alkyl groups, with compounds of the general formula o canton HO wherein R stands for alkyl. The dyestuffs thus obtained can be treated in substance or on the fibre with chroming agents and be transformed into chrome complex compounds.

As diazo compounds preferably used according to the present invention may be enumerated: 2-aminophenol-4-sulfonic acid, 2-aminophenol- 4,6-disulfonic acid, 4-chloro-2-aminophenol-6- sulfonic acid, 6-chloro-2-aminophenol-4-sulfonic acid, 3.4.6-trichloro-2-aminophenol e 5 sulfonic acid, l-nitrofl-aminophenol-G-su1fonic' acid, 6- nitro-2-aminophenol-4-sulfonic acid, 4-chloro- 2 aminophenol 5- sulfonic acid, 4 methyl-2- aminophenol-5-sulfonic acid, 4-benzoylamino-2- aminophenol-S-sulfonic acid, G-benzoyl-amino- 2-aminophenol-4-sulfonic acid, Z-aminophenol- 4-carbamic acid-ethyl-ester-S-sulfonic acid, 2- aminophenol-G-carbamic acid-ethyl-esterl-sulfonic acid and so on.

The new coupling components which are used in preparing the dyestuffs according to the present invention can be obtained by treating 1.7- aminonaphthol with alkylglycol esters of chloroformic acid, preferably in presence of a binding agent, such as sodium or potassium carbonate, chalk and the like. These compounds are difficultly soluble in water, but easily soluble in ethanol and acetone.

The coupling of the diazotized o-aminophenol sulfonic acids witltthe coupling components of the above cited structure is carried out in the conventional manner in an aqueous solution in presence of an alkaline'agent, the new dyestuffs being thus produced in a good yield.

As compared to similar dyestufis prepared according to the process described in British Patent No. 597,542 from 7-hydroxynaphthyl-1-carbamic acid alkyl esters, the new well crystallizable dyestuifs possess the advantage of being better soluble, while possessing the same good fastness properties. They are especially suitable for being used as afterchroming dyestufis and most of them are suitable for the neutral one-bath chrome dyeing process. When treated in substance with chroming agents they can be transformed into valuable well crystallized chrome complex compounds. When dyed on wool according to the after-chroming or to the one-bath chroming process they give grey, bluish-grey, blue and olive tints of good fastness properties to light and very good fastness properties to washing and milling.

The chrome complex derivatives dye wool from an acid bath in similar, but rather more brilliant shades of good fastness properties and in level shades.

The following examples, without being limitative illustrate the present invention, the parts being by weight.

Example 1 22.4 parts of 4-chloro-2-aminophenol-6-sulfonic acid are diazotized and coupled in the presence of an excess of sodium carbonate with a solution of 26.1 parts of 1-(7-hydroxynaphthyl) carbamic acid methylglycol ester dissolved in 300 parts of water in presence of 4 parts of sodium hydroxide. The dyestuff thus obtained is isolated by salting out and filtering; in dry state it is a dark violet powder, soluble in concentrated sulfuric acid with a bluish-red coloration. The dyestufi possesses the formula It dyes woolaccording to the one-bath chrome dyeing process from a neutral bath in brilliant blue-green shades possessing an excellent washing, milling and light fastness.

The coupling compound used above has been prepared by reaction of chloroformic acid methylglycol ester (B. P. 13 mm.: 58-59 C.) with 1.7- aminonaphthol and has the melting point of 96 C.

For the preparation of the chrome complex compound the quantity of the dyestuff obtained as above is suspended in 1,600 parts of water containing 75 parts of sulfuric acid and '75 parts of chrome alum and heated under a reflux condenser to the boil for 24 hours. After cooling down the dyestuff, which precipitates in a well crystallized form, is filtered oif and dried. dry state, it is a dark violet powder, soluble in concentrated sulfuric acid with a bluish-red coloration.

The new chrome complex compound dyes wool" from a sulfuric acid bath into blue shade possessing excellent fast-mess to washing. and mill-- ing and good fastness to light.

Example 2 22.4 parts of fonic acid are diazotized and coupled in the presence .of. an excess of sodium carbonatewith 275 parts. of l-(l-l-rydroxynaphthyl) -carbamic acid ethylglycol ester dissolved in 300 parts of water together. with 4 parts-of sodium hydroxide; The dyestuff. thus obtained is isolated by. salting out and filtering and is, in dry state, a darkpowder soluble in concentrated sulfuric acid with a-bluish-red coloration. Its formulais:

our on? It' dyes wool from a neutral bathaccording to the one-bath chrome dyeing process. into bril liant bluish grey shades possessing very good.fastness properties to washing, to milling,v and vto light.

Th'e'coupling component used inv thisexample has been obtained by treating ill-aminonaphthol with ohloroiornziic acid-eth'ylglycol ester (B. P. 14 mm.; 6'l68 C.) and melts at 102C.

For the preparation of the chrome complexwell crystallized form is illteredoff and"dried.' In dry state it is a dark violet'powder, soluble in concentrated sulfuric acidwith a-bluish-red coloration. It dyes wool from a sulfuric acid bath into blue shades possessing excellent fastness to washing and milling-and good-'fastness .to light.

Example 3 22.4 parts of 4 chloro-2-aminophenol-6-sulfonic acid are diazotized and coupled in the presence of an excess of sodium carbonate with 30.3 parts of l-(7-hydroxynaphthyl)-carbamic acid-n-b-utylglycol ester dissolved in 300 parts.

of water together with 4 parts of'sodium hydroxide.

a dark violet powder, soluble in concentrated sul 4-chloro-2-aminophenole6-sul+ After cooling down, the

The dyestuif thus obtained;- is isolated by salting out and filteringandlis, in dry state,.

furic acid with a bluish-red coloration. Its formula is:

HOgS- N=N lmcm-o-omomomcm This-*dyestulf dyeswool froma neutral bath according to the-ione-batl'l chrome dyeing-process into brilliant blue grey shades possessing very good fastness to washing, milling and light.

Thecoupling component used above has been obtained" by treating 1.7-aminonaphthol with chloroformic acid-n butyl-glycolester (B. P. 14 mm'; 93-949 '0.)

' Example 4 23.4.. partsi' of 4-nitro-2-aminophenol-6-sulfonic acidsare diazotized and coupled in presence of a suitable quantity of sodium carbonate with 27.5 parts of 1-(7-hydroxynaphthyD-carbamic acid ethylglycol ester; dissolved in 300- parts ofwater together with 4- parts" of sodium hydroxide". The-new dyestufi isisolated by'salt ing itoutand-"filtering. In dry state itis'a black powdersoluble in concentrated sulfuric acid with ared'coloration:

Itsformula-is:

The new dyestuff 'dyes woolaccordingto the onebath chroming or after-ch'roming. method into olivegreen to green shades that possess very good fastness to light,,to milling-and to washing.

Forthe preparation of 'th'echromecomplexcompound the. quantity. of the .dyestuff obtained as above described is'suspended in 1200 parts I of 1 water containing parts. of sulfuric acid (10 and 50 partsofchrome alum and'heated under:a refluxcondenser to the boil for 24. hours. After cooling .down the'chrome complex precipitates practically totally. in form of-fviolet-black. needles which canbewell filtered and which are soluble'inwater'with a'green coloration.- Indry state the" chrome containingdyestufi is adark powder soluble: in concentrated sulfuric acid with a Bordeaux redcoloration; It dyes -wool'from. a mineral acid bath into olive-green shades, possessing "excellent. fastnessftoiwashing, to millingand to light.

What I l'claim "is z.

1. A monoazo 'dyestufi corresponding tov the formula":

wherein R stands fonan orth oeamlnophenol-sulfonic acid radical.

5 6 2. A monoazo dyestuff corresponding to the 5. The monoazo dyestuff of the formula. formula 03 OH 0H 7 OH I 1103s N=N- Ems =N 6 EN i L NH =0 1 10 J30 $C2H4-O C235 wherein R1 stands for a member selected from the group consisting of chlorine, nitro, benzoylamino and NH.COO lower alkyl.

3. The monoazo dyestufl of the formula 15 WILLY STEINEMANN OH OH 1 REFERENCES CITED HO5S 2N The following references are ofrecord in the EN 20 file of this patent:

| UNITED STATES PATENTS 1 Number Name Date $C1H4-OC2H5 2,073,470 Fleischhauer Mar. 9, 1937 4. The monoazo dyestuff of the formula 2,037,425 Boyer et July 20, 1937 2,447,163 Conzetti Aug. 17, 1948 I NO;

FOREIGN PATENTS H038 N: Number Country Date 588,771 Great Britain June 3, 1947 T J0 597,542 Great Britain Jan. 28, 1948 (1:0 

5. THE MONOAZO DYESTUFF OF THE FORMULA 